[m-rev.] diff: mercury_cairo: Do not enumerate possible return statuses.

[Peter Wang]

Do not try to exhaustively enumerate possible status values after
creating cairo objects.  It is error prone and unnecessary.

extras/graphics/mercury_cairo/cairo.image.m:
extras/graphics/mercury_cairo/cairo.pdf.m:
extras/graphics/mercury_cairo/cairo.ps.m:
extras/graphics/mercury_cairo/cairo.recording.m:
extras/graphics/mercury_cairo/cairo.svg.m:
	As above.  After creating a cairo object, return the status
	to the user whether successful or not.
---
 extras/graphics/mercury_cairo/cairo.image.m     | 24 ++++++-----------------
 extras/graphics/mercury_cairo/cairo.pdf.m       | 25 ++++++------------------
 extras/graphics/mercury_cairo/cairo.ps.m        | 26 ++++++-------------------
 extras/graphics/mercury_cairo/cairo.recording.m | 24 ++++++-----------------
 extras/graphics/mercury_cairo/cairo.svg.m       | 25 ++++++------------------
 5 files changed, 30 insertions(+), 94 deletions(-)

diff --git a/extras/graphics/mercury_cairo/cairo.image.m b/extras/graphics/mercury_cairo/cairo.image.m
index 7aa59c7..1360731 100644
--- a/extras/graphics/mercury_cairo/cairo.image.m
+++ b/extras/graphics/mercury_cairo/cairo.image.m
@@ -90,24 +90,12 @@ create_surface(Format, Width, Height, Surface, !IO) :-
 		(int)W, (int)H);
     Status = cairo_surface_status(raw_surface);
 
-    switch (Status) {
-        case CAIRO_STATUS_SUCCESS:
-            Surface = MR_GC_NEW(MCAIRO_surface);
-            Surface->mcairo_raw_surface = raw_surface;
-            MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
-            break;
-        
-        case CAIRO_STATUS_NULL_POINTER:
-        case CAIRO_STATUS_NO_MEMORY:
-        case CAIRO_STATUS_READ_ERROR:
-        case CAIRO_STATUS_INVALID_CONTENT:
-        case CAIRO_STATUS_INVALID_FORMAT:
-        case CAIRO_STATUS_INVALID_VISUAL:
-            Surface = NULL;
-            break;
-        
-        default:
-            MR_external_fatal_error(\"Mercury cairo\", \"invalid status\");
+    if (Status == CAIRO_STATUS_SUCCESS) {
+        Surface = MR_GC_NEW(MCAIRO_surface);
+        Surface->mcairo_raw_surface = raw_surface;
+        MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
+    } else {
+        Surface = NULL;
     }
 ").
 
diff --git a/extras/graphics/mercury_cairo/cairo.pdf.m b/extras/graphics/mercury_cairo/cairo.pdf.m
index a6f3e56..d3b8ff3 100644
--- a/extras/graphics/mercury_cairo/cairo.pdf.m
+++ b/extras/graphics/mercury_cairo/cairo.pdf.m
@@ -112,25 +112,12 @@ create_surface(FileName, Width, Height, Surface, !IO) :-
     raw_surface = cairo_pdf_surface_create(FileName, W, H);
     Status = cairo_surface_status(raw_surface);
 
-    switch (Status) {
-        case CAIRO_STATUS_SUCCESS:
-            Surface = MR_GC_NEW(MCAIRO_surface);
-            Surface->mcairo_raw_surface = raw_surface;
-            MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
-            break;
-
-        case CAIRO_STATUS_NULL_POINTER:
-        case CAIRO_STATUS_NO_MEMORY:
-        case CAIRO_STATUS_READ_ERROR:
-        case CAIRO_STATUS_INVALID_CONTENT:
-        case CAIRO_STATUS_INVALID_FORMAT:
-        case CAIRO_STATUS_INVALID_VISUAL:
-            Surface = NULL;
-            break;
-
-        default:
-            MR_external_fatal_error(\"Mercury cairo\",
-                \"unknown PDF surface status\");
+    if (Status == CAIRO_STATUS_SUCCESS) {
+        Surface = MR_GC_NEW(MCAIRO_surface);
+        Surface->mcairo_raw_surface = raw_surface;
+        MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
+    } else {
+        Surface = NULL;
     }
 #else
     Supported = MR_NO;
diff --git a/extras/graphics/mercury_cairo/cairo.ps.m b/extras/graphics/mercury_cairo/cairo.ps.m
index 12984ea..ffada5f 100644
--- a/extras/graphics/mercury_cairo/cairo.ps.m
+++ b/extras/graphics/mercury_cairo/cairo.ps.m
@@ -164,27 +164,13 @@ create_surface(FileName, Width, Height, Surface, !IO) :-
     raw_surface = cairo_ps_surface_create(FileName, W, H);
     Status = cairo_surface_status(raw_surface);
     
-    switch (Status) {
-        case CAIRO_STATUS_SUCCESS:
-            Surface = MR_GC_NEW(MCAIRO_surface);
-            Surface->mcairo_raw_surface = raw_surface;
-            MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
-            break;
-
-        case CAIRO_STATUS_NULL_POINTER:
-        case CAIRO_STATUS_NO_MEMORY:
-        case CAIRO_STATUS_READ_ERROR:
-        case CAIRO_STATUS_INVALID_CONTENT:
-        case CAIRO_STATUS_INVALID_FORMAT:
-        case CAIRO_STATUS_INVALID_VISUAL:
-            Surface = NULL;
-            break;
-
-        default:
-            MR_external_fatal_error(\"Mercury cairo\",
-                \"unknown PostScript surface status\");
+    if (Status == CAIRO_STATUS_SUCCESS) {
+        Surface = MR_GC_NEW(MCAIRO_surface);
+        Surface->mcairo_raw_surface = raw_surface;
+        MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
+    } else {
+        Surface = NULL;
     }
-
 #else
     Supported = MR_NO;
     Status = CAIRO_STATUS_SUCCESS;
diff --git a/extras/graphics/mercury_cairo/cairo.recording.m b/extras/graphics/mercury_cairo/cairo.recording.m
index 4312008..7b03f88 100644
--- a/extras/graphics/mercury_cairo/cairo.recording.m
+++ b/extras/graphics/mercury_cairo/cairo.recording.m
@@ -130,24 +130,12 @@ create_surface(Content, MaybeExtents, Surface, !IO) :-
 
     Status = cairo_surface_status(raw_surface);
 
-    switch (Status) {
-        case CAIRO_STATUS_SUCCESS:
-            Surface = MR_GC_NEW(MCAIRO_surface);
-            Surface->mcairo_raw_surface = raw_surface;
-            MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
-            break;
-
-        case CAIRO_STATUS_NULL_POINTER:
-        case CAIRO_STATUS_NO_MEMORY:
-        case CAIRO_STATUS_READ_ERROR:
-        case CAIRO_STATUS_INVALID_CONTENT:
-        case CAIRO_STATUS_INVALID_FORMAT:
-        case CAIRO_STATUS_INVALID_VISUAL:
-            Surface = NULL;
-            break;
-
-        default:
-            MR_external_fatal_error(\"Mercury cairo\", \"invalid status\");
+    if (Status == CAIRO_STATUS_SUCCESS) {
+        Surface = MR_GC_NEW(MCAIRO_surface);
+        Surface->mcairo_raw_surface = raw_surface;
+        MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
+    } else {
+        Surface = NULL;
     }
 #else
     Supported = MR_NO;
diff --git a/extras/graphics/mercury_cairo/cairo.svg.m b/extras/graphics/mercury_cairo/cairo.svg.m
index a27e49b..fbb511a 100644
--- a/extras/graphics/mercury_cairo/cairo.svg.m
+++ b/extras/graphics/mercury_cairo/cairo.svg.m
@@ -126,25 +126,12 @@ create_surface(FileName, Width, Height, Surface, !IO) :-
     raw_surface = cairo_svg_surface_create(FileName, (int)W, (int)H);
     Status = cairo_surface_status(raw_surface);
 
-    switch (Status) {
-        case CAIRO_STATUS_SUCCESS:
-            Surface = MR_GC_NEW(MCAIRO_surface);
-            Surface->mcairo_raw_surface = raw_surface;
-            MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
-            break;
-        
-        case CAIRO_STATUS_NULL_POINTER:
-        case CAIRO_STATUS_NO_MEMORY:
-        case CAIRO_STATUS_READ_ERROR:
-        case CAIRO_STATUS_INVALID_CONTENT:
-        case CAIRO_STATUS_INVALID_FORMAT:
-        case CAIRO_STATUS_INVALID_VISUAL:
-            Surface = NULL;
-            break;
-        
-        default:
-            MR_external_fatal_error(\"Mercury cairo\",
-                \"unknown SVG surface status\");
+    if (Status == CAIRO_STATUS_SUCCESS) {
+        Surface = MR_GC_NEW(MCAIRO_surface);
+        Surface->mcairo_raw_surface = raw_surface;
+        MR_GC_register_finalizer(Surface, MCAIRO_finalize_surface, 0);
+    } else {
+        Surface = NULL;
     }
 #else
     Supported = MR_NO;
-- 
2.1.2